The invention relates to a cleat assembly for drive tracks for tracked vehicles, particularly for ski slope grooming, with a cleat member that includes anxe2x80x94in cross-sectionxe2x80x94essentially U-shaped base from a connection shank and two U-shanks connected with it via a flex rim that fit together and end opposite to the connection shank by forming an end piece of the cleat member.
Such a cleat assembly is known from DE 90 06 13 U and DE 29 602 940 by the same applicant. The cleat assembly is formed from shaped stock running perpendicular to the drive track, and is usually attached to the drive track so that it may be removed. After attachment, the end pieces are basically perpendicular to the drive track, and serve at least partially to grip the surface on which the tracked vehicle moves.
As the tracked vehicle moves over the surface, flexure in sections of the rubber drive track may be observed near the flex rim between the U-shanks and connection shanks. Because of these bends, damage to the drive track appears after a certain operating time because of the repeated flexure of the drive track over the flex rim.
The object of this application is to solve the task of improving the type of cleat assembly described at the outset so that is allows longer drive track service life with its simple and low-cost design.
This object is solved in connection with the features of the preamble of claim 1 in such a manner that the flex rim includes a roll bead that is projecting essentially outward from the connecting shank and bent upward toward the end piece. As the tracked vehicle moves, the drive track is no longer bent along the flex rim, but rather is bent along the roll bead. Thus, much less load is imposed on the drive track, and the service life of the drive track is increased in a simple, low-cost manner. In connection with this, one must be aware that corresponding deformations or bends in the drive track appear especially in the area of the track wheels, as well as in the area of the horizontally-mounted drive track, when the cleat assemblies are pressed toward the drive track. It has been noted that the cleat assembly based on the invention may be used both for drive tracks during winter use of the tracked vehicle and for so-called xe2x80x9csummer drive tracks.xe2x80x9d
In order to form a roll bead without using a separate piece, the roll bead may be formed as one piece with the cleat element. In this case the flex rim known from the state of the art formed from the perpendicular meeting of connecting shank and U-shank may be expanded into a roll bead that projects outward and upward.
In order to be able to upgrade cleat assemblies already in use with a roll bead as necessary, the roll bead may be formed on at least one lateral end of a support washer locatable between the connecting shank and the drive track. In this manner, all tracked vehicles may be upgraded with cleat assemblies according to the state of the art as described by this invention. Further, there exists the option of providing properly-shaped roll beads on the support washer, depending on the used drive track and its potential flexure. That means that a roll bead of lesser size with a smaller crimping radius may be used for a small degree of drive track flexure in the direction of the cleat assembly.
Since a tracked vehicle may drive either forward or backward, corresponding flexures of the drive track relative to the cleat assembly may occur on both sides. To deal with this, the roll bead may be formed on both sides of the cleat member.
It is conceivable for a roll bead with simply-manufactured bend to be shaped like part of a circle, particularly with a quarter-circle shape, on its surface at least partially turned toward the drive track.
In order to maintain the same amount of bending or flexing of the drive track on both sides of the cleat member, the roll bead may be shaped with the same bend radius on both sides of the cleat member. In this case, the cleat member or the support washer is formed symmetrically with respect to the roll bead. It is equally possible to shape the roll bead to be asymmetrical in case the tracked vehicle drives preferably in one direction.
In order to provide adequate bending or flexing conditions for the drive track, the bend radius of the roll bead might be at least twice as great as the bend radius of the flex rim. The magnitude of the bend radius is determined by the track tension, track material, the ground, etc.
The cleat assembly across from the cleat member might have a lower support washer so that the drive track is arranged between the support washer and the cleat member or upper support washer to ensure simple and reliable attachment of the cleat assembly to the drive track.
Since the drive track may also evince bends or flexures in the area of the lower support washer, the lower support washer might include at least one roll bead on its lateral ends in an outward manner and bent away from the drive track corresponding to upper support washer.
Larger bends or flexures of the drive track than in the area of the upper support washer may occur near the lower support washer, especially near the track wheels of the tracked vehicle. Therefore, the roll beads on the upper and lower support washers may be configured with different bends. In order to simplify support washer manufacture, it is also conceivable that the roll beads be shaped the same on the upper and lower support washers.
In order to maintain a better connection between cleat assembly and drive track, the support washer on its lower side facing the drive track might include at least one projection extending and at least partially projecting in the longitudinal direction of the cleat assembly profile. This grips at least partially into the elastic drive track material. Further, such a projection may serve at least partially to prevent the intrusion of water, ice, or snow between the cleat assembly and drive track. Such material intruded between the cleat assembly and drive track may attack the surface of the drive track under certain weather conditions. Further, the clamping effect between the cleat assembly and drive track may be increased, which may prevent underside holes, for example.
Both above-mentioned effects of such a projection may be further improved if numerous such projections are arranged essentially parallel to one another on the underside.
A simple form of a support washer results if it is shaped essentially as a flat-bottomed tub with laterally arranged roll beads. The support washer may be manufactured from a suitable profile, as may the cleat member.
In order to enable a certain closing shape with respect to the cleat member when such a support washer is used, it is conceivable that the interior edges of the roll beads of the support washer may at least partially contact the U-shanks from the outside. In this manner, the cleat member is adjustable within the support washer so that it is held at least partially in proper position.
It is again emphasized that, depending on the application and usage conditions of the tracked vehicle, it is desirable for the roll bead bend radii at the ends of a support washer and/or of the upper and lower support washers to be different.
For a roll bead integrated directly into the cleat member, it is conceivable that the connection shank include at. least one projection on its side facing the drive track. This acts similarly to the projection or projections on the underside of a support washer to improve grip on the drive track and at least partially prevent intrusion of water, snow, or ice in this area.
A simple embodiment example is conceivable in which a rim bead is integrated into the cleat member whereby the rim bead at the cleat member has an essentially flat upper side extending in the direction of the U-shank. This may extend perpendicular to the U-shank and blend into the U-shank via a bend at the end.
Particularly good grip to the drive track may conceivably also be achieved if the projections are arranged offset with respect to each other on the underside of the connection shank or the upper support washer and lower support washer.
In order to provide interchangeability for the upper and lower support washers, thus reducing manufacturing costs, the upper and lower support washers may be shaped identically.
A simple option for attaching the cleat assembly is conceivable in which the cleat member and/or upper support washer and/or lower support washer include a threaded hole used to secure the cleat assembly to the drive track.
One must note that it is possible according to the invention to use a cleat assembly based on the above-mentioned state of the art in which only the lower support washer is constructed according to the invention. In this case, a bending or flexure of the drive band over the relatively sharp flex rim of the cleat member results, however, on the inner surface of the drive track that bends and flexes more sharply, a guiding around the roll beads is achieved.
Regarding the materials of the cleat member and support washer, it must be mentioned that these may be selected based on the use of the tracked vehicle. For example, materials such as aluminum, steel, or alloys containing them for the cleat member, and the same materials as well as plastic for the support washers, may be recommended. Materials with similar characteristics may also be used for the cleat member and/or the support washer.